All adults over the age of 18 in the UK will now be offered the booster jab, as the Government continues to tackle the Omicron variant of Covid-19.
The booster rollout has been expanded over fears that the new variant is more transmissible and potentially more resistant to the vaccines.
And the third doses will now be fast tracked, with the gap between the second and third doses cut down from six to three months.
Until now it was only over-40s and those with particular health conditions that were eligible for a booster shot.
All adults will now be offered their booster doses in the original priority list, going down in five-year age brackets.
READ MORE: Downing Street Press Conference: LIVE updates as UK set to announce expansion of Covid-19 booster vaccine programme
It was also announced today that all children aged 12 to 15 will be offered second doses.
Up to now, children in that age gap had only been advised to have one dose of the vaccine against Covid.
The expansion of the vaccination programme comes as six further cases of the Omicron variant have been detected in the UK.
Severely immunosuppressed people could also be given access to another booster, meaning some will be given their fourth dose over winter.
Deputy Chief Medical Officer Professor Jonathan Van-Tam said many scientists agree that Omicron is "of increased concern".
He went on to stress there is still a "very high degree of current uncertainty" about the new variant.
The Medicines and Healthcare products Regulatory Agency (MHRA) chief executive backed these new recommendations by the Joint Committee on Vaccination and Immunisation (JCVI) today.
The changes were announced in a live Downing Street briefing this afternoon, hosted by Professor Jonathan Van Tam.
Professor Wei Shen Lim, JCVI chair, said: “Having a booster dose of the vaccine will help to increase our level of protection against the Omicron variant.
“This is an important way for us to reduce the impact of this variant on our lives, especially in the coming months.
“If you are eligible for a booster, please take up the offer and keep yourself protected as we head into winter.”
Jonathan Van-Tam added: "there are far more things we don’t know yet than things we do know", including whether the variant could resist vaccines.
Health chiefs have insisted that boosters are best administered before a wave, to give a few weeks for immunity to develop.
